Benin Moat
Edo State, Nigeria · built 1280
The Benin Moat (Edo: Iyanuwo), also known as the Benin City Iya, the Inner City Iya of Benin or the Wall of Benin, is a large earthwork within Benin City in Nigeria's Edo state, which formerly encircled the city at the time of the Benin Empire.
Monument data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).